Rocket launcher



Dec. 20, 1960 w, D BOBCO ET AL 2,965,001

ROCKET LAUNCHER Filed May zo, 1954- 4 sheets-sheet 1 -Willilll'rrl.4 D.Einbau v 'E 'Wnll A- Kun-11:1 Rudolph E..5"cE1-\n ATTORNEYS Dec. 20,1960 w. D. Bosco ErAL 2,965,001

ROCKET LAUNCHER Filed May 2o, 1954 sheets-sheet 2 91S w8 @SNS m..

.Extern K nvvENrofas William D. Ember:

ArrazA/:Ys

Ewuld A.-Kump Rudnlph E- ...Il Il lllllll @WA Sw. @m QW,

@um H Lll Dec. 20, 1960 w. D. BoBco ETAL ROCKET LAUNCHER 4 Sheets-Sheet3 Filed May 20, 1954 ROCKET LAUNCHER 4 Sheets-Sheet 4 Filed -May 20,1954 www? bb. Q om s m flo o f\ m N pn mh m n .E v n u@ W o WBK am LAE.f dh T1@ M m wm WER m Y e -mmwrmll United States Patent ROCKE'I` LAUNCHER William D. Bobco, Berwyn, and Ewald A. Kamp and Rudolph E. Stern,Chicago, Ill., assignors, by mesne assignments, to the United States ofAmeri as represented by the Secretary of the Army Filed May 20, 1954,Ser. No. 431,306

6 Claims. (Cl. 89-1.7)

This invention is an automatic, rapid firing gun.

An object of the invention is to provide a gun having a high cyclicfiring rate, of the order of 800 rounds per minute for projectiles insizes normally associated with artillery.

Another object of the invention is to provide a gun which will index,lire and eject a round with a minimum of moving parts.

Another object of the invention is to provide a gun in which thestripping, ramming and extracting operations of conventional weapons areeliminated.

A further object of the invention is to provide a gun having a barrel,the breech end of which is spaced from a back plate to receive a roundtherebetween, in axial alignment with the barrel, the case of said roundbeing substltuted for the firing chamber and breech block,conventionally used.

v A further object of the invention is to provide gas operated means forindexing the rounds to tiring position and reciprocating a breechclosing collar in timed relation to the arrival and departure of theround.

A further object of the invention is to provide a novel scar mechanismfor arresting the movement of the indexing means when the last round hasbeen tired or the external feeding mechanism fails.

A still further object of the invention is to provide ring means on thegun for igniting the booster charge in the round only when the gun is inbattery position.

Other objects and advantages will be apparent from the followingdetailed description and the accompanying drawings, in which:

Figure l is a vertical longitudinal sectional view of a gun embodyingthe present invention.

Figure 2 is a transverse sectional view to an enlarged i. lscale on theline 2-2 of Figure 1 and illustrating a conventional magazine connectedthereto.

Figure 3 is a top plan of the gun with parts broken away.

4Figure 7.

Figure 9 is an enlarged sectional view of the 'breech closing mechanism.

Figure l 0 is. a sectional view of the drive spring assiem-I bly andcombined charger. v I Figure 11 is a sectional view of the. lll Pin.

Figure 12 is an enlargedview of the sprocke t,assem bly and its brakemechanism.

Figure 13 is an enlarged detail view of the 'cam slide.

2,965,001' 'Patented Dee. 2o, 1960 lCC Figure 14 is a fragmentary viewon the line 14-14 of Figure 9, and

Figure 15 is a fragmentary top plan view of the cover plate.

The present invention was devised to increase the tire power of weaponsusing gun boosted rocket ammunition wherein the rocket and boosterpropellant is housed entirely within the cartridge case, herein referredto as a round The rounds are fed to tiring position without belts orlinks. Therefore such operations as stripping from the belt, ramming,and extracting spent casings from the breech are eliminated with acorresponding saving of time and mechanical parts, as well as apotentially large increase in rate of fire. In our invention thecartridge case serves as the firing chamber of a gun. A sliding collarsurrounding the barrel and movable in synchronism with the indexingmechanism, replaces and functionally substitutes for the breechmechanism of a conventional or prior art gun.

In the drawings, wherein for the purpose of illustration, is shown oneform of the invention, the reference character 5 indicates the receiverof the gun. A vertical transverse support 6 forms a part of the receiverand is provided with reinforcing side plates 7 (Figures 3 and 5).Trunnion pins 8, Figure 3, are formed on the support 6 for pivotalconnection with a suitable mount, not shown. I'he terms forward andrearward" used herein mean, respectively, the movement of components4toward the muzzle end of the weapon and toward the back plate.

A cylindrical housing 9 is secured at its rear end to the support 6 andat its forward end by upstanding side plates 10 (Figures l and 3)forming a part of the receiver. An internal circumferential shoulder 11is formed in the housing 9 near its rear end and abuts an externalcircumferential shoulder 12 on barrel 13 litting, within the housing.The breech end of the barrel extends rearwardly beyond the rear end ofthe housing 9 and has a portion thereof externally screw-threaded toreceive an internally screw-threaded nut or collar 14 for clamping theshoulder 11 against the shoulder 12. As best shown at Figure 9, theforward end of the nut is circumferentially reduced externally tounderlie and fit the internally reduced end of the housing 9. A setscrew 15 in the housing engages the nut 14 to prevent rotation of thenut relatively to the housing. An additional means for securing thebarrel in the housing is provided by a pivoted latch 16 (Figure 9) whichis adapted to seat in a depression 17 in the barrel.

Rearwardly of the support 6 and adjacent the rear end of the barrel abracket 18 is secured to the receiver by screws 19 (Figures l and 3). Aguide rail 20 extends the entire length of the upper faceof the bracketand is formed integrally therewith. A second bracket 21 secured to thereceiver 5 by screws 22 near the rear end of the receiver also has anintegral guide rail 23 extending the full length of the upper facethereof. A shaft 24 (Figures 1, 6 and 12) having a screw-threadedforward end 25 fixed against rotation in a similarly threaded opening inthe bracket 18, extends rearwardly through an opening in the secondbracket 21. The longitudinal axis A of the shaft 24 (Figure 1) ispositioned .parallel to and below the longitudinal axis B of the barreland is spaced therefrom a substantial distance, as will be hereinaftermore fully explained.

-A sprocket assembly 26 (Figures 6 and l2) which is free to rotate onthe shaft 24, comprises a sleeve 27 having end sprocket wheels 28a and28b formed therewith.

A sprocket wheel 29l (see also Figures 2 and 6) spaced intermediate thesprocke't'wheels 28, is also formedintegral with the sleeve 27. Both ofthe end sprockets 28 ai'efor'n'iedfwith concave recesses30 (Figure l)between adacent-arms lwhich arespacediat 90 degree intervals. Y

The sprocket wheel 29 has similarly spaced arms 32 and concave recesses33 in longitudinal alignment respectively with the 'arms J31 and4concave recesses 30 of ithelsprocket wheels 28. The concave recesses ofall Aspro'cket wheels are"`shaped to cradle the particular '-type ofround to be. used. A

' A'magazine 34 lis shown in Figure 2 wherein rounds R are fedhorizontally and Itransversely of the gun 'between upper rails 3S andllower-rails 36 by a presser bar 37 secured to a piston rod 38. Thepiston -rod has a piston 39 secured thereto for reciprocation in acylinder 40. Fluid pressure is admitted "to the cylinder througha-conduit 41 from asource, notl shown. It isto be understood that themagazine herein shown is -merely for vthe purpose of illustrationandthat many v'different types can be substituted, as occasion demands.f

One form of vround R which is adapted to be used in the presentinvention is disclosed and claimed 'in va lcoending application of E. A.Kamp et al., Ser. No. 406,618, filed January 27, 1954, for Rocket Round(Ord Case 4044) and comprises a casing 42 which has a cap A43 forclosing itsrear end. The cap is formed with a circumferential shoulder44 which abuts the guide rail 23 on thevrear bracket 21 as vclearlyshown upon Figures 1 and 3. At its forward end the casing carries asleeve 45 iixed therewith -and the rear face of which formsv acircumferential shoulder which is slightly -spaced from'theforward-'face of guide rail 20 of *the forward bracket 18,whereby'each'round as it moves between-the "guide railsis vlrrxitedv inaxial motion A"to an *amount less than the clearance-"between the roundandthe firing pin face and the rear face of the barrel. The round R maycontain a spin type rocket '46, 'a booster charge 47 for initiatingilight and a detonating means 48, -as more specifically described `intheaforesaid copending application. 'A back plate '50 is Asecuredto `thereceiver by pins 51 as shown in Figures 3 and 4.

A cover Aassembly 52 is vprovided at its front end lwith two bored lugsI53 which are pivotally'secured in recesses 54 in top of support 6 bypins `55, as shown in Fifures 3 and 5. The rear end of the cover isprovided with three transversely-spaced bored lugs 56, Figure 4, whichare secured in recesses '57a lat the top of the back plate '50 by a pin51a. It will 'be apparent on referring to Figures l, 4 and 5 that thecover 52 may be raised when vthe rear pin 51a is removed and the coverpivoted on the front pins 55. Guide ra'ils 57 and 58 are secured to theunder side of the cover and-retain the rounds in their respectiverecesses in the sprocket wheels as they are picked Aup and indexed bythe sprocket assembly.

A sprocket brake sleeve 59 is secured against rotation in the rearbracket 21 by a -key 60, Figure 12, and is bored to journal thesprocketshaft 24 and to have axial motion therealong. The forward end ofthe brake sleeve is enlarged and formed with cam surfaces 61 which coactwith similarly'shaped cam surfaces 62 on an insert 63 which is keyed tothe rear hub of the sprocket assembly. Figure l2 shows the camsin theirposition about midway of the indexing movement of the sprocket. Theshaft 24 extends rearwardly through an opening 64 in Vthe back plate 50andhas positioned thereon compression spring means 65 lsuch asBelleville washers, but other types of spring means can be used as founddesirable. The spring is confined between washers 66 or the like theforward one of which is urged thereby against the rear end of the brakesleeve V59 to exert a desired pressure by a nut 67 threaded on the shaft24 rearwardly of the back washer 66. Near the end of the indexingmovement of the sprocket the cam surfaces 62 contact the cam surfaces 61on the brake sleeve and through the cushioning action of the springmeans 65 rapidly decelerate the motion of th'c'sprocket'assembly. 'Attheend of the indexing rotation of the sprocket assembly the at tip of the'cams 61 and 62 are 'in contact and a round of ammunition is in tiringposit-ion,

at-which time .a dwell in `the .tiring ycycle is effected, as will laterbe more fully explained. In the present embodiment of the invention, thesprocket assembly rotates intermittently in a counterclockwise directionas viewed from the breech end of the gun. The arms 32 of theintermediatesprocket wheel 29 are bored radially at 70, Figure l2, tohouse spring pressed rollers 71, 71a, 71b and 71c as best seen in Figure6. The

rollers are free to rotate on .stub shafts 72 which are" limited intheir outward radial movement by pin vand slot connections 73. A springelement 74 'housed ineach of the bores 70 urges the stub shafts andtheir rollers radially outwardly for -a purpose to be hereinafter morefully disclosed.

As shown in `Figures l, 2 and 3 the gun has been charged and can befired as soon as a manually operated switch, not shown, is closed.Thereafter firing continues until the switch is opened. An automaticfiring switch assembly 75 as shown in Figures 7 and 8 is positioned inopenings in the feed side of the receiver and com'- prises two springpressed contact pins 76 and 77 whieh are insulated from the receiver bysleeves 78 of dielectric material. A bus bar 79 is embedded in theforward -end of the reduced guide tongue of an indexing slide 68, 'to behereinafter described and engages the two contact pins 76 and 77 toclose a tiring circuit to the firing pin assembly 49. The 'bus bar isinsulated from 'the slide by dielectric Imateriallt).

The tiring -pin assembly 49 comprises a housing 157, Figure ll, having-a vflangel 158 on one end, and having its other end screw threaded toreceive asimilarly screw threaded -nut 159for securing the housing intheback plate 50. A single electrode 160 -is axially positioned within abore 163 in the housing 157 and is insulated therefrom by -sleeves 161of dielectric material. The

bore 163 is internally screw threaded at 164 and receives a similarscrew 'threaded retaining lplug 165. A lead 165a from the automaticfiring vswitch 75 is connected to the' electrode 160. -A 'helical springelement 166 is housed within an enlarged end of the electrode -andfurges a tiring pin 167 into contact with the detonating means 48 in theround. The spring element also serves to conduct voltage to the firingpin.

When the round is tired and the projectile has traveled a short distanceinto the barrel, the expanding gas from the booster charge 47 finds itsway through a port 81, Fig. l, in the barrel 13 and a bore 82 in thesupport 6 to enter a cylinder 83 positioned beneath the barrel. Slidabiymounted in the cylinder is a piston S4 having a piston rod 85 whichextends rearwardly into engagement with the forward end of an indexingslide 68 to `be-later described. Extending forwardly from the piston 84isa second piston rod 86 which forms part ofl a buffer assembly 87.'The-forward end of cylinder 83 is closed by screw threaded engagementwith'a cylindrical spacer 83a which also acts as a guide forA the pistonrod S6. The buffer assembly comprises a cylinder 88 in which a'piston 89is positioned on and intermediate the ends of an elongated piston rod90. The forward end of piston rod 90 engages a buffer spring 91 which isrestrained within a. housing 92. The cylinder 88 is screw threaded tothe forward end of the cylindrical spacer 83a and has its rear end 93contracted to tit about and guide the piston rod 86. A piston rod guide94 is screw threaded into the forward end of the cylinder 88. Recoiltype oil is placed in the cylinder 88 between the piston 89 and itsclosed end 93. The piston 89 is slightly smaller in diameter than thebore of-its cylinder to permit the passage of oil when placed underpressure during reciprocatioh of'the buffer assembly. When the expandinggas enters the lcylinder 83 and drives the piston 84 and piston rods 85and 86rearwardly, the buffer spring 91 expands at which time the oil inthecy'linder 88 'is' forced to pass between 'the-cylinder wall andpiston and comes t0' rest l infront of the cylinder. The return movementof the piston will be buffed by the slow passage of oil to the otherside thereof.

Indexing slide 68 is mounted for reciprocation in a forward and rearwarddirection in guideways 69, Figs. 5 and 6, within the receiver andadjacent the sprocket assembly. The upper surface of the indexing slideis formed as the surface of a cylinder of about 90 angular extent andwith its axis coincident with the axis A of shaft 24 and is slotted toreceive and guide the rollers 71, 71a, 71b, and 71c on the sprocketwheel 29. When the gun is in battery position the two lowermost rollersare positioned in the rear ends of longitudinal straight slots 95 and96, as can be seen by reference to Figure 13. When the slide is drivenrearwardly by the piston 84 and piston rod 85 the rollers 71 and 71a areguided by the slots 95 and 96 to a position at the front end of theslide. During this step in the indexing cycle the sprocket assembly isheld against rotary movement and the dwell, hereinbefore referred to, isaccomplished. Near the forward end of the slots 95 and 96, steps 95' and96' respectively, are formed to prevent the rollers from returning totheir respective slots on forward movement of the indexing slide. Thespring elements 74 in the sprocket wheel 29 urge the stub shafts androllers outwardly to the lower level of their respective slots for thispurpose and in a manner obvious from comparison of Figs. 6 and 12. Theforward stroke of the slide 63 is the driving stroke which rotates thesprocket assembly 90". A sinusoidal cam path is provided by a slot 97inslide 68, Fig. 13, which communicates with the for ward end of slot 95and the rearward end of slot 96, so that during this forward stroke theroller 71 isforced tofollow the slot to the position formerly occupiedby the roller 71a. The roller 71a is rotated away from'the slot 96through the cutout portion 96b. A ste'p 97l is formed at the junction ofthe slots 96 and 97 to keep the roller 71a in its slot 96. lt will beunderstood that the steps 95 and 97 are formed by the lesser depth,respectively, of slot 95 at its intersection with slot 97 and of 97 atits intersection with slot 96.

A breech closing mechanism in the form of a colar 99 (see Fig. 9) isslidably mounted on the rear end of the barrel 13 and closes the gapbetween the breech end of the barrel and the forward end of the casingof round R. An internal circumferential beveled face 100 on the rear endof the collar 99 engages a complementally beveled externalcircumferential face 101 on the forward end of the sleeve 45 to move theround rearward to insure contact between the primer 48 and the firingpin assembly 49 and also to serve to align the case with-the barrel,when the faces are pressed into contact. A copper ring 45b is mountedfor limited axial translation witnin a bore in the forward end of sleeve45. The inner periphery of the ring is formed as the'su'rfaces of twofrusto-conical surfaces to define a circular ridge of slightly lesserdiameter than the rotating band 46a of the rocket. As the rocket movesforwardly in its case 42, the rotating band contacts the ring 45b anddrives it forwardly into contact with the barrel 13. The rising gaspressure acts on the internal and rear surfaces 0f n'ng 45b therebyholding the ring tightly against the rear surface of the barrel and atthe same time expanding the ring against its seat in sleeve 45 to effectadditional sealing action against loss of pressure. Each sealing .ringis ejected with its cartridge after tiring. Movement of the collar iseffected by means of a lever 102, forked at its upper end as indicatedat 104, Figure 9 and rotatable on a fulcrum element 103 intermediate itslength, and having its upper forked ends 104 positioned in seats formedon opposite sides of the collar 99 for translation of motion thereto.The opposite end of the ,lever terminates in a rounded head 104a whichis seated zin Aa socket 105 -in a. sliding block 106. Angle bars 107,1Figure5, secured to a` bottom plate of the receiver guide the block forstraight line movement. A link 108, best shown upon Figure 9, is securedby a pivot element 109 to the block and to a bell crank 110 by the pivot'element 111. Referring more particularly to Figure 14, the bell crankis secured to a bracket 112 by a pivot element 113 and carries a roller114 on its free end. A cam groove 115 is formed on the bottom of theindexing slide 68, Figure 5, and receives the roller 114 forreciprocating the breech closing collar in timed relation to theindexing cycle. The cam groove 115 extends throughout the length of theindexing slide and has an offset portion 116 at its rear end. See Figure13. At the beginning of a tiring cycle the round is fired and theindexing slide is forced back. The rollers 71 and 71a ride in thestraight slots 95 and 96 and hold the sprockets and the round in thefiring position during the rearward movement of the slide. At thebeginning of this rearward movement the roller 114 is guided from theolset portion 116, into the straight portion 115 of the cam groove, andby means of the bell. crank and linkage the lever 102 forces the collar99 forward to release the tired round and remain out of the path of theincoming round. During the forward stroke of the inde ing slide thebreech closing colrar 99 remains in a forward position until the roller114 is returned to the offset portion 116 of the cam groove' 115. Ashereinbefore stated, the forward stroke of the indexing slide causes thesprockets to rotate and thus index a new round into firing positionafter which the aligning collar is moved rearvviardly into contact withthe sleeve of the new roun lInAorder to permit free movement of theround through the launcher, a clearance is vprovided between the overalllength of the round and the tiring pin ange 158 and the rear face of thebarrel. In order to compensate for manufacturing tolerances in theoverall length of various rounds a thrust compensating assembly 1.17 isxed in the support 6 to carry the fulcrum element 103 of lever 102.

A plunger 11'8 having a head 119 is slidable in a cylinder 120. Springwashers or other suitable means 121 urge the piston and piston headrearwardly. A plunger frod 122 extends forwardly from the plunger andpasses through a hole in the cylinder head. A nut 123 is screw threadedon the end of plunger rod 122 and provides the means for adjusting theposition of the fulcrum element 103 of the lever 102.

Detents 124 and 125, Figures 2, 4 and 5, slidably mounted on the upperguide rails 57 and 58 respectively', hold the round in position to bepicked up by the sprocket assembly after the round has been fed intosuch position. Each detent is slidably mounted on an arcuate plate 126,for movement in an arcuate path about the axis A. Each plate is securedto its respective guide rail. As each round enters the receiver itengages the cam faces 127 of the detents and cams them upwardly in theaforesaid arcuate path against the downward urge exerted by springpressed plungers 128 which are housed in cylinders 129. The limit ofdownward movement of the detents is determined by fingers 130 of thedetents, which engage an angle bar 131, connecting the rails 57 and 58thereby stops further movementof the detents in the downward direction.l

Secured to the receiver by screws or otherwise is a bracket 132, Figure6, which carries a sear 1 33 rotatable on a pivot element 134 parallelwith axis A. The sear has an upstanding arm 135 anda horizontal arm136'which engages a notch 137 on the indexing .slide 68 and holds `theslide in its rearward position when the last round in the magazine isfired. A spring'pressed plunger 138 carried in a casing 139 fixed tobracket 132 tends to thrust the arm toward the incoming rounds butrecedes -under pressure of the round to hold the arm 136 out of frominspection -of and charger assemblies are connecte'd to the indexingslide to return it to battery position. As'the assemblies are identicala description of one will Sguiee for both. Referring to Figures l and10, a front wall 140 of the receiver 5 has secured thereto as by meansof screws 141 a housing 142 to which a guide tube 143 is secured asat`144. A rod 145 is positioned axially of the tube 143 and is guidedfor axial reciprocation by a nut 146 whichis serrated at its outer edgesto permit the free passage of air, and by an opening in the support 6.Encircling the rod 145 is a driving or return spring 147 which isconfined between the support 6 and the nut 146. The rod 145 extendsrearwardly through the support '6 and is secured to the indexing slide68 as shown at 148 in Figure 10. The forward end of the guide tube 143extends beyond the nut 146 to provide room for a free piston 149. A cap150 seals the end of guide tube and is bored and screw-threadedcentrally to receive a fluid pressure conduit 154 which is connected toa fluid pressure source, not shown. It is apparent that when pressureenters the cylinder 143, the piston 149 will be driven rearwardly intocontact with the nut 146 and consequently the rod 145 will force theindexing slide rear wardly. A buffer 151, Figures l and 4, of anydesired type and material is secured in theback plate 50, to absob theimpact of the rearward motion of the indexing sli e.

The operation of the gun is as follows:

Fluid pressure is admitted to the feed mechanism and a round R, inthe'feed mechanism, is forced into engagement with the sprocketassembly. The sear is lifted by contact of thevincoming round with thearm 135. AWhen fluid pressure .is admitted to the charger assemblies,through' tubes 154, the indexing slide is forced rearwardly, compressingthe drive springs 147. Exhausting the charger assemblies causes theslide to move forward rotating the sprocket assembly 90 and sliding thealigning collar 99 into contact with the front end of the round. Thelast 25 of movement of the sprocket assembly is decelerated by the camsurfaces 61 and'62 of the brake mechanism due to engagement between thesloping surfaces of the cams and the resulting rearward movement ofsleeve 59 against the thrust of springs 65. The firing circuit is closedby an external switch, not shown, and the round is fired. Firingcontinues as long as the switch is closed. If the magazine is exhaustedor a round fails to get past the detents 124 and 125 the arm 136 of thesear will drop into the notch 137 of the indexing slide and stopoperation of the gun.

While we have disclosed a form of the invention presently preferred byus, various changes and modifications will occur to those skilled in theart after a study of the present disclosure. Hence the disclosure is tobe taken in an illustrative rather than a limiting sense; and it is ourdesire and intention to reserve all modificationsfalling within thescope of the subjoined claims.

Having now fully disclosed the invention, claim and desire to secure byLetters Patent is:

l. In a gun having a barrel, a cylinder having a port in communicationwith said barrel to admit fluid pressure from the barrelinto saidcylinder, means operated by fluid pressure in said cylinder for feedingrounds successively into position for firing. said means including asprocket wheel to receive and advance the successive rounds, a brakemechanism disposed coaxially with and responsive to the rotationcelerating said wheel in position for firing a round therein from saidbarrel comprising a slidable member having a first plurality offorwardly facing cam surfaces, a second plurality of rearwardly facingcam surfaces integral to the what we rearward end of said sprocketwheel, a spring means normally urging said slidable member in a forwarddirection. whereby said first and said second cam surfaces aremaintained in meshed r'elation, and a cam slide coacting with saidsprocket wheel for rotating said sprocket by and in response toactuation of said slide.

of said sprocket wheel for de- 2. In a gun having a frame, a barrel, acylinder having a port in communication with said barrel to admit fluidpressure from the barrel into said cylinder, piston lmeans reciprocablein said cylinder in response to fluid pressure therein, brackets carriedby said frame, a shaft iourna'led in said brackets and disposed parallelto and spaced below the longitudinal axis of said barrel, a sprocketwheel-rotatably mounted on said shaft to receive a plurality of roundsand to advance the same for successive firing from said barrel inresponse to rotation of said wheel, a cam, means mounting said cam forreciprocation axially-of said barrel, means reciprocating said cam byand in response to actuation of said piston, means rotating saidw'heel'by and in response to reciprocation of said cam, and brakingmeans for said wheel mounted on said shaft responsive to rotationthereof to decelerate said wheel into firing position comprising asleeve encircling said shaft and mounted for axial movement only in oneof said brackets, said sleeve defining at its forward end an enlargedportion having a plurality of forwardly facing cam surfaces, an insertintegral on the rearward end of said sprocket wheel, said insertdefining a plurality of rearwardly facing cam surfaces similar to saidcam surfaces on said sleeve Yand compression spring means mounted onsaid shaft normally biasing said sleeve in a forward direction wherebysaid cam surfaces on said sleeve are in mesh with said cam surfaces onsaid insert.

3. In a frame, a gun having a barrel, a cylinder having a port incommunication with said barrel to admit 'fluid pressure from thepropellant of a projectile launched from said barrel into said cylinder,brackets carried b y said frame, a shaft fixed in said brackets anddisposed parallel to and spaced below the longitudinal axis of saidbarrel, piston means reciprocable in said cylinderin response to fluidpressure therein, a sprocket wheel vassembly rotatably mounted on saidshaft and formed to receive a plurality of rounds and to advance thesame in succession into alignment with said barrel for firing therefromin response to rotation of said assembly, a cam, means mounting said camfor reciprocation axially of said barrel, said cam responding to actionof said piston for movement in one direction, recuperator meansconnected to said cam for movement in the opposite direction, meansrotating said assembly by and in response to reciprocation of said camand holding said assembly during a dwell in the firing cycle, and meansbraking the movement of said assembly toward the end of each indexingmovement comprising a tubular sleeve defining an integral enlargedforward portion having forwardly facing cam surfaces thereon, saidsleeve being keyed against rotation in one of said brackets and to slideaxially therein, an vinsert'integral to the rearward face of saidsprocket wheel assembly defining rearwardly facing cam surfaces adaptedto mesh with said forwardly facing cam surfaces on said sleeve, a firstwasher slidably mounted on said shaft and adapted to abut the rearwardend of said sleeve, a second washer on said shaft secured againstrearward movement thereon and a plurality of Belleville springsencircling said shaft and disposed between said washers, said springsnormally biasing said sleeve forwardly to maintain said cam surfaces onsaid sleeve and said insert in meshe'd relation, said means beingresponsive to the rotation of said assembly.

4. An automatic gun for firing rocket-cartridge type rounds having aframe. a barrel, a back plate secured to said frame and spaced from thebreech end of said barrel a distance substantially equal to the lengthof 'the round, a cylinder having a port in communication "th said barrelto admit fluid pressure from the barrel into said cvlinder. meansoperated by fluid pressure in said cylinder for feeding roundssuccessively into axial alignment with said barreland abutting said backplate, said means including a sprocket wheel to receive and advance 'thesuece'ssive rounds', said wheel having radially extending rollers, afirst cam for translating motion to said radiallyfextending rollers forrotating said wheel by and in response to actuation of said first cam, acollar reciprocable on said barrel and abutting the front end of saidround to accurately position said round, a second cam for translatingmotion to said collar, said means comprising a pivoted bellcrank lever,a roller on one arm thereof slidable in said second cam, a block havinga socket therein, means mounting said block for reciprocation axially ofsaid barrel, a link connecting said block and said bellcrank, aresiliently cushioned support having a pivot element, a lever mounted onsaid pivot element intermediate its ends, one end engaging the socket insaid block the other end terminating in a yoke to embrace andreciprocate said collar in response to actuation of said second cam, anda clutch mechanism for holding said wheel in position during tiring ofthe round and reciprocation of said collar.

5. In a gun having a frame, including a back plate, a barrel, a cylinderhaving a port in communication with said barrel to admit liuid pressurefrom the barrel into said cylinder, piston means reciprocable in saidcylinder in response to liuid pressure therein, a sprocket wheelrotatably mounted to receive a plurality of rounds and to advance thesame for successive tiring from said barrel in response to rotation ofsaid wheel, a recprocable indexing slide having cam grooves in itssurface, means on said wheel engageable in said cam grooves for rotatingsaid wheel in response to reciprocation of said slide, a resilientlyheld tiring pin mounted in said back plate in alignment with saidbarrel, a tiring switch comprising a pair of spring pressed contactssecured to said frame and a circuit closing bar secured to said indexingslide and bridging said spring pressed contacts when said slide is inforward position, and means for conducting voltage to said firing pin.

6. In a gun having a receiver, a cover for said receiver, a barrel, acylinder in uid communication with said barrel, liuid pressureresponsive piston means reciprocable in said cylinder, axially alignedspaced sprocket wheels rotatably mounted in said receiver for receivinga pluralty of rounds and to advance same for successive tiring from saidbarrel in response to rotation from said wheel, a reciprocal indexingslide having cam grooves in its surface, means carried by said wheel fortranslating movement to said wheel, means for holding said rounds inseated position in their respective recesses in said sprocket wheels asthey are picked up and rotated towards iiring position comprising, guiderails secured to the under side of said cover, each said rail having anarcuate lower edge spaced radially from and equiangular to the outerperiphery of each said sprocket wheel, an arcuate plate secured to oneside of each said rail, a spring loaded detent slidably mounted on eachsaid arcuate plate, its lower edge forming a continuous equiangular arcwith said arcuate edge on each said plate, there being a cam surface atone edge of each said detent adapted to engage an incoming roundentering said receiver and lift said detent to permit said round toenter its respective recess in said sprocket wheel, there being anintegral finger on each said detent limiting its downward movement and apivoted sear delining an upstanding and a horizontal arm, said scarrotating in a counterclockwise direction upon engagement with a round insaid sprocket wheel to lift said horizontal arm from engagement withsaid slide to permit reciprocal movement thereof and to rotate in aclockwise direction when said sprocket wheel is empty to bring saidhorizontal arm into engagement with said slide and stop operation ofsaid gun.

References Cited in the iile of this patent UNITED STATES PATENTS564,043 Benet et al. July 14, 1896 2,450,929 Ashworth et al. Oct. 12,1948 2,464,920 Carter Mar. 22, 1949 2,575,368 Thomsen Nov. 20, 19512,638,339 Taylor May 12, 1953 FOREIGN PATENTS 125,126 Great Britain Apr.17, 1919 589,177 Great Britain June 13, 1947 639,766 Great Britain Iuly5, 1950 687,826 Great Britain Feb. 18, 1953 288,467 Switzerland May 16,1953 1,040,335 France May 20, 1953

